As a related-art electronic component including a coil, for example, a laminated-type inductance element described in Japanese Unexamined Patent Application Publication No. 2007-214424 is known. The laminated-type inductance element includes a spiral coil made of an internal conductor, a first nonmagnetic body layer disposed perpendicularly to a coil axis of the coil, and a second nonmagnetic body layer disposed in the internal conductor.
With the laminated-type inductance element, the first nonmagnetic body layer is disposed to cross the coil, and thus the coil forms an open magnetic-path structure. As a result, even if a current of the laminated-type inductance element becomes high, a rapid decrease in inductance value due to magnetic saturation is not likely to occur. That is to say, the direct-current superposition characteristic of the laminated inductance element improves.
Incidentally, an electronic component including a coil is sometimes used for a DC-DC converter in an electronic device, such as a mobile telephone, etc. An electronic device, such as a mobile telephone, etc., has a normal state in which normal operation is performed, and a standby state in which many functions are stopped. In the normal state, a relatively high current flows through the coil of the electronic component included in the DC-DC converter (hereinafter referred to as a high-output current area). In the standby state, a weak current flows through the coil of the electronic component included in the DC-DC converter (hereinafter referred to as a low-output current area).
In the electronic component, in the low-output current area, a direct-current superposition characteristic in which a sufficiently large inductance value is obtained is desirable. At the same time, in the electronic component, in the high-output current area, a stable direct-current superposition characteristic in which an inductance value does not change significantly, even if a direct current value flowing through the coil is changed. In this manner, a direct-current superposition characteristic, in which a sufficiently large inductance value is obtained in a low-output current area while a stable inductance value is obtained in a high-output current area, is called a stair-like direct-current superposition characteristic.
However, in the laminated-type inductance element described in Japanese Unexamined Patent Application Publication No. 2007-214424, a stair-like direct-current superposition characteristic cannot be obtained. More specifically, in the laminated-type inductance element, a rapid decrease in inductance value due to magnetic saturation does not occur, and thus the laminated-type inductance element has a direct-current superposition characteristic in which an inductance value monotonously and gradually decreases with an increase in direct current. Accordingly, there has been a problem in that a laminated-type inductance element is difficult to be applied to a DC-DC converter.